In a conventional thermal management system for an automotive engine, a cooling circuit circulates a coolant liquid, generally of water and antifreeze. The cooling circuit generally includes a coolant pump powered by the engine crankshaft or electronic control module. The coolant pump propels the coolant liquid through the cooling circuit. Engine thermal management systems are generally designed to promote engine and coolant liquid warm-up after cold start and promote engine cooling during normal vehicle operation.
The coolant follows a path through cooling passages in the engine block, through cooling passages in the engine head, and then directly through hoses to a radiator or heater core. At cold start, coolant is directed from the engine head through hoses to the heater core to warm the engine and passenger compartment efficiently. When the engine and passenger compartment are sufficiently warmed, a thermostat signals the change in coolant flow from heater core to radiator. Upon the signal of the thermostat, the coolant is routed from the engine head through hoses to a radiator to remove excess heat from the engine and promote a constant operating temperature during vehicle operation. The coolant liquid then travels from the radiator and/or engine heater core through a hose and back to the coolant pump.